60 inch Petersen Mechanical Allows for Seamless Upgrades at 50 Year Old Water Treatment Plant

60” steel lined concrete pipe sealed for valve replacement.

Calgary, Alberta, Canada

INTRODUCTION

Petersen’s solution allowed the city to replace valves without shutting off the water supply including draining, work, repressurization and superchlorination.

PROBLEM

The City of Calgary needed to replace valves connected to 60” steel lined concrete pipes. To minimize pipe hoop loads, an external strongjack bracket system would need to be created to transfer axial and shear forces back into a square junction box rather than into the pipe wall. The pipes came off of the junction box wall at a 5° Angle. No permanent anchoring could be attached to the junction box. The placement of the plug needed to be done underwater with the hatch 45 meters away from the plug placement. The pipes needed to be sealed off for 3 weeks while the valves were replaced. All pipe plug components needed certification for NSF 61 potable water. The solution needed to be reviewed and stamped by a third party as well as Petersen Products.

   

SOLUTION

Working with City of Calgary and Graham Construction Co, Petersen Products engineers designed a neutrally buoyant mechanical plug with a strongjack secured to the junction chamber. The plug could be installed by a single diver. The strongjacks handled the compound forces of the angular load by using a series of welded shims. Shims were also used to pre-tension the entire system. From purchase to shipment took 16 weeks. This included design, review, fabrication and testing.

RESULT

MINIMAL DOWNTIME - Petersen’s solution allowed the city to replace two fresh water valves for 3 weeks each without shutting off the water supply during that time.

COST SAVINGS - Without having to shut down the entire system, the City of Calgary was able to avoid the costs related to shutting down. With the response time they were able to stay on their original repair schedule.